Schedule Of Valuation And Qualifying Accounts (Detail) (Allowance for Doubtful Accounts, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 1,230		$ 3,078		$ 4,757
Charged to Costs and Expenses	1,792	[1]	(1,171)	[1]	352	[1]
Charged to Other Accounts		[2]		[2]		[2]
Deductions	(242)	[3]	(677)	[3]	(2,031)	[3]
Balance at End of Period	$ 2,780		$ 1,230		$ 3,078

[1] Charges relate to provisions for doubtful accounts

[2] Reflects the impact of acquisitions

[3] Deductions relate to the write-off of accounts receivable deemed uncollectible